It's a modern choice.
I like it.Adalyn does sound a bit like "madelyn" without a "M" to me. Sadly a bit like Elodie- which as much as I love it sounds like Melody.
I think you may get spelling troubles- Adelyn, Adeline, Adaline etc
Possibly pronounciation issues- I would say it as "ad-a-lyn" but a PP thought it was ADA-lyn

That said, I like it.
I have a soft spot for Mackenzie too. Agree on the 'c'.